(a) Field of the Invention
The invention relates to a multicomputer network which includes a novel interconnection system for interconnecting the computers of the network, as well as an interface means for connecting the computers of the multicomputer network to the interconnection system.
The invention also relates to the novel interconnection system comprising a time shared high speed parallel bus and a controller therefore.
The invention also relates to the novel interface means.
(b) Statement of the Problem
Many factors, including increasing demand for computing power and memory capacity coupled with decreasing costs of microcomputers, have contributed to the growth of research and application in the area of multiple microcomputer systems. One of the uses of such multiple microcomputer systems is distributed computing wherein a complex algorithm is decomposed into several modules. Some, or all, of the modules are then executed simultaneously on different computers of the multicomputer system.
Any algorithm can be decomposed in different ways, and each different decomposition may require a different intercomputer communication pattern for the multicomputer system. Thus, the computers may be connected to each other with communications in one direction only. Or they could be connected to each other with communications in both directions. Or a tree pattern could be formed.
The problem of finding the optimal decomposition for any algorithm, that is, the one which minimizes the overall run time, is still an open research problem (see for example, P. H. Enslow, "Multiprocessor Organization, A Survey", Computing Surveys, Vol. 9, No. 1, 1977, pp. 103-129).
Thus, in order to test for the optimality of different decompositions, it would be desirable to have a flexible arrangement wherein the communication patterns of the computers in a multicomputer network can be easily and quickly rearranged. With such a flexible network, different decompositions can be experimentally studied and evaluated.
For such an arrangement, the interconnection systems are critical. Such interconnection systems have been the subject of study at universities, for example, Cm* at Carnegie-Mellon University (R. J. Swan, S. H. Fuller, and D. P. Siewiorek, "Cm*, A Modular Multimicroprocessor", Proc. AFIPS Nat. Comp. Conf., 1977, pp. 637-644), the MICRONET project at the State University of New York at Buffalo (L. D. Wittie, "MICRONET: A Reconfigurable Microcomputer Network for Distributed Systems Research", Simulation, Sept. 1978), and the .mu.* project at Politecnico di Torino (P. Civera, G. Conte, D. Del Corso, F. Gregoretti, and E. Pasero, "The .mu.* Project: An Experience with a Multimicroprocessor System", IEEE Micro, May 1982, pp. 38-49). However, these interconnection systems lack the desired and required flexibility and the control for the interconnection means.